Only this week 80 % discount on e-learning courses of C# .NET
Get up to 60 % extra points for free! More info
C# week

Lesson 6 - Dictionaries (maps) and sets in Java

In the previous lesson, Multidimentional arrays in Java, we introduced and tried the linked list and then made a turn to Multidimensional arrays in Java. Today's Java tutorial's going to be about dictionaries (maps) and sets.

Dictionaries (maps)

The idea of the dictionary is that we often need to access an element using a key. This concept works the same as with an array where the keys (indexes) are numeric. The dictionary allows us to index using any data type, e.g. a string. We then access the elements of the collection using these strings. An analogy can be found in a real paper dictionary where we have each string word associated with the translation, explanation, other meanings, etc.

The data in this collection is stored in a special way known as hashing. This approach allows us to


 

...End of the preview...
Continue further

You will gain knowledge worth hundreds of thousands for a few crowns

You've come here and that's great! We believe that the first lessons showed you something new and useful
Do you want to continue the course? Go to the premium section.

Limited offer: Learn all knowledge and save money

Buy lessons and exercise submitting one by one 80 points
Buy all currently available lessons with exercise submitting and other features for an exclusive price 68 points ($6.12)
Currently, you have 0 points
By buying this exclusive package, you'll have access to all 13 lessons in this course including exercise submitting while saving $1.08. This offer is limited for the first lessons only with an additional exclusive 15% discount.
You gain 68 points for adding an article to the site, or for $7.20 $6.12

Warning, by buying just this lesson you'll lose the limited 15% discount for the package of all the lessons.

Buy only the lesson 10 points
Currently, you have 0 points
You gain 10 points for adding an article to the site, or for $0.90

This article is licensed: Premium, by buying this article, you agree with the terms of use.

What will you get from us in the next lessons?
  • Unlimited and permanent access to individual lessons.
  • High quality IT knowledge.
  • Skills to help you get your dream and well-paid job.

Article description

Requested article covers this content:

In this Java tutorial, we'll introduce dictionaries and sets, describe the HashMap and HashSet classes and try these new collections on examples.

You gain points by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.

Article has been written for you by Petr Štechmüller
Avatar
Activities